I Was Reincarnated and Became a Slave?

"WTH what's on my neck, Masaka, this is a slave collar!! I've become a slave! Damn it, I just slept, why did I become a slave?" "Miss Song, this will be your personal slave from now on. He will protect you at school"... When I woke up, I traveled across the world and became a slave! How is this different from normal time travel! I'm really broken! Why do others travel to another world, but I travel to such a developed world? God has eyes, please let me, a young man go! Let me, a young man, go! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.